This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-094197, filed Mar. 28, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to product environmental load evaluation method of evaluating environmental load of products and a system therefor.
2. Description of the Related Art
In recent years, environmental issues have socially become significant. Because of this, it is required to consider reducing the load that the products exert on environment as well as considering the influence that production activity in factory exerts on environment. Thus, life cycle assessment (LCA: Life Cycle Assessment) attracts attention. LCA is a technique for analyzing and evaluating the load that the products exert on environment through life. In other words, LCA grasps environmental load through life cycle of products (raw materials acquisition, manufacturing, distribution, usage, disposalrecycling), and is used for reduction of environmental load. LCA represents overall evaluation of products in product life. Further, LCA can be utilized for improving the load scientifically or rationally by grasping load such as air pollution, the resource efficiency, a quantity of waste, etc., quantitatively. However, LCA needs many time and labor in evaluation when performing minute processing study for the whole life cycle of a product.
The products such as home electric appliances are large in number and in kind, and occupy large environmental load. Therefore, LCA evaluation is important. In particular, LCA is required for checking what kind of environmental load is generated in the life cycle of a product, in which stage of the cycle it is generated, and how heavy it is. It is also required for checking what should be improved and in which stage the improvement should be done, so as to lighten the environmental load. There is proposed a technique useful for subjecting products of a short development cycle such as home electric appliances products to life cycle evaluation at the design stage.
The environmental load over the life cycle of products can be grasped by the above prior art. However, since the environmental load calculated by the database of an environmental load emission intensity unit is different greatly from an actual value, it is a problem what kind of database should be employed. Reliable data for building up the environmental load emission intensity unit database are data of an xe2x80x9cInput-Output tablexe2x80x9d for example. The Input-Output table includes everything of demand and feeding of every field of domestic industry entirely. Therefore, if this Input-Output table is used, the emission intensity unit dated back to the source can be calculated. Further, the reliable data are not limited to the Input-Output table.
If the emission intensity unit is standardized as an industry standard, it may be used. Further, the process analysis method and input-output analysis method are known as data calculation methods. The process analysis can calculate comparatively exact value, but it is not effective due to needs of vast labor. The input-output analysis has an advantage capable of calculating wide data since it includes everything of all the domestic industry. However, since it indicates a mean value of the domestic industrial products, it includes data different from an actual value.
Further the hybrid system combining the process analysis with the input-output analysis method in order to offset the weak points of both is proposed. It is original LCA to calculate the entire environmental load dated back to the source such as the material and resource. However, it is very difficult to date back to the material and resource due to non-maintenance of data and so on, actually. The Input-Output table is used due to advantages to save the trouble for collecting all data. However, the rippling effect of the Input-Output table is limited in this country, and do not consider environmental load to occur with manufacturing in overseas like imported materials.
The imported materials such as aluminum are accompanied with such large overseas loads that are impossible to ignore. Therefore, it has been pointed out that the environmental load does not fit the fact only by domestic rippling effect. A technique to combine environmental load to occur in manufacturing and the transportation in overseas with environmental load of the country is proposed as a method to solve such weak points. This is a hybrid system with a process analysis and an input-output analysis method reported by Central Research Institute of Electric Power Industry. This method adds the environmental load in overseas to the domestic environmental load estimated by an input-output analysis method by a cumulative manner, to calculate the emission intensity unit including overseas emission.
In this report, five kinds of goods: coal, crude oil, LPG (LNG), iron ore and aluminum ingot are treated as imported goods. The environmental load in overseas is investigated as for these five goods. Environmental load on five imported goods is estimated by the process analysis. However, the environmental load of the other majority goods is calculated with they being considered as the domestic production.
By the method, the environmental load emission intensity unit including the environmental load to occur about all materials abroad is value to be near to reality and desirable. However, only these five goods are not enough. The nonferrous metals such as copper, lead, zinc occupy a lot of ratios in component part of home electric appliances, for example. For the reasons, errors of the environmental load calculated by ignoring overseas load of nonferrous metal increase.
Further, even if the improvement that seems to make it reduce environmental load by a method to change materials configuration of products is performed, if iron and non-iron do not use environmental load unit consumption obtained based on the similar calculation condition, accurate evaluation cannot be obtained. Accordingly, this cannot apply to product development for environmental load reduction. However, it is extremely difficult to perform data search with respect to all the imported goods in reality.
It is an object of the invention to provide a product environmental load evaluation method including setting criteria to determine the range to be investigated in order to estimate more realistic environmental load, and calculating the environmental load unit consumption that is considered environmental load to occur in overseas about materials selected according to this criteria.
According to the first aspect of the invention, there is provided a product environmental load evaluation method comprising: computing fuel input coefficients, inverse matrix coefficients and input coefficient matrix of imported goods referring to an Input-Output table regarding domestic goods; generating emission coefficients referring to an existing data stochastic document; estimating a direct emission matrix based on fuel input coefficients and emission coefficients; computing environmental load of the domestic goods based on the inverse matrix coefficients and direct emission matrix; computing overseas environmental load emission coefficients of the imported goods based on overseas parameter every addition of an imported good; computing imported good environmental load based on the input coefficient matrix of the imported goods and the overseas environmental load emission coefficients; and computing product environmental load by adding the domestic good environmental load to be provided fixedly and the imported good environmental load updated every addition of an imported good.
According to the second aspect of the invention, there is provided a product environmental load evaluation program recorded on a computer readable medium, comprising: means for instructing a computer to compute fuel input coefficients, inverse matrix coefficients and input coefficient matrix of imported goods referring to an Input-Output table regarding domestic goods; means for instructing the computer to generate emission coefficients referring to an existing data stochastic document; means for instructing the computer to estimate a direct emission matrix based on fuel input coefficients and emission coefficients; means for instructing the computer to compute environmental load of the domestic goods based on the inverse matrix coefficients and direct emission matrix; means for instructing the computer to compute overseas environmental load emission coefficients of the imported goods based on overseas parameter every addition of an imported good; means for instructing the computer to compute imported good environmental load based on the input coefficient matrix of the imported goods and the overseas environmental load emission coefficients; and means for instructing the computer to compute product environmental load by adding the domestic good environmental load to be provided fixedly and the imported good environmental load updated every addition of an imported good.